Pens come in a variety of types, shapes and sizes and range in cost from as little as a few cents to several hundred dollars. The present invention relates to an inexpensive pen.
Relatively low cost ball-point pens can be found in both the retractable type, in which the writing tip extends from and retracts into a barrel, for example, by pressing in a push button at the head end of the barrel or by rotating one portion of the barrel relative to another portion, and the fixed type, some of which have removable caps, in which the writing tip is permanently affixed to the barrel. Generally, the retractable types are somewhat more costly to produce and, therefore, more expensive than the fixed types. The retractable types are generally preferable from the point of view of being transportable in a pocket or purse, inasmuch as the writing tip can be retracted and will not, therefore, deface a pocket or purse or objects in them. The detachable caps of fixed type ball-point pens tend to get lost. Moreover, the barrel of a pen with a detachable cap can easily become detached from the cap when the pen is carried in a pocket or purse, in which case a shirt can be ruined or items in a purse or pocket defaced.
Ball-point pens, and for that matter all writing instruments, are not particularly convenient to carry, but most people like to carry a pen anyway. When clipped to a shirt pocket or coat pocket, a pen can poke or press against the wearer from time to time. Some pockets are not deep enough to fully accept the pen. There is often not enough room in small compartments of purses or in small change purses to receive the conventional ball-point pen.
In recognition of a long felt need for an inexpensive pen that can be carried easily on the person or in small purses with the writing tip protected by a non-detachable cap and at the same time having a size and shape that are conventional and customary for normal writing, the present inventor has previously invented a ball-point pen that is, in a sense, of the retractable type, in that the writing tip is exposed in one configuration and covered and protected in another configuration. In another sense, it is not a retractable type, inasmuch as there is no retraction mechanism for moving the writing tip into and out of the barrel, the writing tip being affixed to the barrel. The pen of that invention is flexible when in the configuration in which the writing tip is covered and protected but is rigid when the tip is uncovered for use. The flexibility of the pen in the configuration when the tip is covered and protected allows the pen to bend when placed in a pocket or a purse so that it can fit conveniently into small pockets and purses and so that it can yield and thereby be more comfortable when carried on the person. Reference may be made to U.S. Pat. No. 4,580,919 issued Apr. 8, 1986 and to U.S. Pat. No. 4,679,954 for disclosures of the basic invention and an improvement, respectively.
The pen referred to above comprises an elongated one-piece barrel having substantially rigid tip end and head end portions joined to each other by an intermediate integral flexible portion, whereby the barrel can be bent at the flexible portion, and a writing tip at the distal end of the tip end portion. A substantially rigid tubular cap member is received telescopically over the tip end portion of the barrel in a manner such that it can be moved along the barrel between (1) a retracted position in which it overlies part of the tip end portion and substantially all of the flexible portion, thus rendering the pen substantially rigid, and (2) an extended position in which it covers the writing tip and leaves the flexible portion exposed, thus protecting the writing tip and rendering the pen flexible. The cap and barrel have interengaging coupling elements that releasably retain the cap member in each of the retracted and extended positions.
In one form (U.S. Pat. No. 4,580,919) the cap member is free to move both rotationally and longitudinally between the extended and retracted positions. It has been observed that when the cap member releases from the retained positions, which requires some amount of force, it may move very rapidly to the other position and then be stopped abruptly. Such abrupt actions can be disconcerting to the user, particularly a user who is not familiar with the pen.
The improvement U.S. Pat. No. 4,679,954 alleviates the tendency for rapid movement by changing the direction of the releasing force from longitudinal to rotational--thus the force to enable shifting of the cap does not result in rapid lengthwise movement. Furthermore, the improvement translates the rotational releasing force on the cap to longitudinal movement by means of slanted portions of the control grooves.
As not infrequently occurs, the solution of one problem creates another, albeit a minor one, as in this case. The improved design requires a precise pattern of rotational and longitudinal motions of the cap to move it between the retracted and extended retained positions. Again, it is the novice user who can encounter minor difficulty; the conditioned user can perform the motions by second nature.
It goes without saying that threaded members are well-known for providing linear motion in response to rotational forces, and threaded elements, including protective caps, removable and non-removable, are known in pens and other writing instruments. The disadvantage of threads is that they are not easy to form. Ordinarily, they are machined, because the tooling to cast or mold them is relatively complicated.